A close look to Angular's new HttpClient Manfred Steyer SOFTWAREarchitekt.at 

About me … • Manfred Steyer • Angular Workshops and Consultancy • SOFTWAREarchitekt.at • Google Developer Expert (GDE) Page ▪ 2 Manfred Steyer 

In the old days, everything was better ;-) 

Just a few examples … 

Http in Angular Http (Service) • Angular 2+ • Most Common Use Cases (80:20 principle) • Experimental • Deprecated with 5.0 HttpClient • Angular 4.3 • A lot of additional features • Full comfort we know from $http 

Contents • Short overview of Basics • Custom Data Formats (Binary, Text) • Progress Information • Interceptors for Extensions • Token-based Security 

DEMO 

angular-crud 

No content

Basics 

HttpClient HttpClientModule and HttpClient from @angular/common/http let url = 'http://www.angular.at/api/hotel'; let headers = new HttpHeaders() .set('Accept', 'application/json'); let params = new HttpParams() .set('city', this.city); this .http .get(url, { headers, params }) .subscribe( hotels => console.debug('hotels', hotels), err => console.error('err', err) ); 

Getting the full HttpResponse save(entity: HotelBooking): Observable { let url = […] let headers = […] return this.http .post(url, entity, {headers, observe: 'response'}) […] } 

Getting the full HttpResponse save(entity: HotelBooking): Observable { let url = […] let headers = […] return this.http .post(url, entity, {headers, observe: 'response'}) .pipe( map((response: HttpResponse) => { console.debug('status', response.status); console.debug('body', response.body); return response.headers.get('Location'); })); } 

Testing 

Main Idea: Mock the HttpBackend HttpClientTestingModule Your Code Test HttpClient HttpBackend Server MockBackend 

Testing it('can load hotels by city', () => { let service: HotelService = TestBed.get(HotelService); let ctrl: HttpTestingController = TestBed.get(HttpTestingController); […] }); 

Testing it('can load hotels by city', () => { let service: HotelService = TestBed.get(HotelService); let ctrl: HttpTestingController = TestBed.get(HttpTestingController); service.find({ city: 'Graz' }).subscribe( hotels => expect(hotels.length).toBe(2), err => fail(err) ); […] }); 

Testing it('can load hotels by city', () => { let service: HotelService = TestBed.get(HotelService); let ctrl: HttpTestingController = TestBed.get(HttpTestingController); service.find({ city: 'Graz' }).subscribe( hotels => expect(hotels.length).toBe(2), err => fail(err) ); let req = ctrl.expectOne('/hotel?city=Graz'); expect(req.request.method).toBe('GET'); […] }); 

Testing it('can load hotels by city', () => { let service: HotelService = TestBed.get(HotelService); let ctrl: HttpTestingController = TestBed.get(HttpTestingController); service.find({ city: 'Graz' }).subscribe( hotels => expect(hotels.length).toBe(2), err => fail(err) ); let req = ctrl.expectOne('/hotel?city=Graz'); expect(req.request.method).toBe('GET'); req.flush([{id: 1, name: 'Hotel Mama'}, {id: 2, name: 'Budget Hotel'}]); ctrl.verify(); }); 

Custom Data Formats (Text and Binary) 

Using XML findById(id: string): Observable { […] return this.http .get(url, { headers, params, responseType: 'text'}) […] } 

Using XML findById(id: string): Observable { […] return this.http .get(url, { headers, params, responseType: 'text'}) .pipe( switchMap(xmlString => { let observableFactory = bindCallback(parseString); return observableFactory(xmlString, parserOptions); }), map(js => js[1].hotelBooking) ); } import { parseString } from 'xml2js'; 

DEMO 

Interceptors 

Idea • Providing a hook • Modify requests and responses globally • Including Headers, e. g. for Auth. • Parsing Data Formats, like XML • Error Handling • Caching • … 

Chain of Responsibility Logic (HttpRequest) Interceptor Interceptor Request Response 

DEMO Sending Access Token for Auth Global Error Handler for Auth 

Conclusion observe: response, events, … responseType: text, blob, … Interceptor Chain The Dark Knight: Best Movie ever! 

Contact und Downloads [mail] [email protected] [blog] SOFTWAREarchitekt.at [twitter] ManfredSteyer